Assessment of skeletal and dental fluctuating asymmetry in two historic Dutch populations

Abstract

The study of human remains in terms of health and disease of past populations is of immense interest to physical anthropologists and bioarchaeologists. One method utilised for such an assessment is fluctuating asymmetry. Fluctuating asymmetry refers to the morphological inequality in bilateral anatomical structures and is considered an indicator of developmental stress. The purpose of this study was to assess and compare the magnitude of skeletal and dental fluctuating asymmetry between and within two populations and to correlate these findings with three other markers of skeletal stress, namely, enamel hypoplasia, cribra orbitalia/porotic hyperostosis and subperiosteal bone reactions. The sample comprised of two urban archaeological samples housed at the University of Amsterdam, the Grote Kerk sample (n=171), representing the general population of the 18th to early 19th century, and the psychiatric hospital sample from Meerenberg (n=106) of the 19th to early 20th century. Left and right measurements were recorded from various traits of the cranium, mandible, humerus, radius, femur, tibia and dentition, from which the fluctuating asymmetry values were calculated. No statistically significant differences between the sexes or age categories were documented, although skeletal fluctuating asymmetry was slightly greater in adults. The Grote Kerk exhibited significantly greater frequencies of subperiosteal bone reactions, while the Meerenberg population exhibited greater frequencies of enamel hypoplasia. Individuals who exhibited one of the three pathological lesions were more asymmetrical than individuals without lesions. No significant differences existed in the level of asymmetry between the two populations. However, the Meerenberg population exhibited slightly greater asymmetry in the facial and vault region of the cranium, and the Grote Kerk population in the long bone lengths. Based on the frequencies and aetiologies of the pathological lesions, it is suggested that the two populations were probably subjected to similar levels of stress, even though the source, timing and duration of stress might have been different. Despite the similar levels of stress, the Meerenberg population was expected to exhibit increased levels of fluctuating asymmetry due to the premise that individuals with mental disorders or deficiencies are developmentally less stable than the mentally healthy. Therefore, the possibility should also be considered that fluctuating asymmetry is not a highly sensitive indicator of developmental stress.